Control Systems
Critical Equipment Control DI-TRONICS® Model # CEC200-000
To efficiently provide fault-tolerant
protection and maximum availability for a steam turbine-driven
centrifugal compressor train, the
critical equipment control system
must be designed to maximize
the availability of the performance
monitoring functions while providing fault tolerant protection for
the STC. The Dresser-Rand critical
equipment control system integrates a two-out-of-three voting
architecture based on its inherent
ability to identify and compensate
for a failed control system
element or field device while
enabling repair without
process interruption.

Introduction
The DI-TRONICS critical equipment control system 200 is an integrated triple modular redundant (TMR) solution for the steam turbine-driven centrifugal compressor
train. The fault-tolerant implementation of this control system is based on extensive
Dresser‑Rand expertise and integrates vibration monitoring, temperature, steam
flow and surge control into a reliable TMR control system package.
At the heart of the critical equipment control system is the Triconex TMR programmable logic controller (PLC) or Tricon Version 9.6 (or higher) PLC. The Tricon PLC
is technologically advanced, flexible in configuration and can be programmed in
many common program languages including ladder logic and function blocks. Steam
turbine governor control and other high-level programs are developed in segregated
function blocks to ensure the highest levels of reliability and system security.
Because the Tricon PLC is manufactured and used globally in thousands of critical
applications, the critical equipment control system offers worldwide, off-the-shelf
availability of replacement parts, as well as local technical assistance, training
and support. The use of advanced packaging techniques provides easy access
to internal panel components and the smaller panel offers a distinct advantage in
areas with limited space. In addition, with features such as modular architecture,
advanced diagnostics, hot module insertion and quick-connect field wiring, users are
assured that their needs for flexibility and expansion will be met.

Standard Configuration and System Features
The standard DI-TRONICS critical equipment control system is integrated into a freestanding enclosure and includes the Tricon V9.6 (or
higher) PLC configured with the following standard features:
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Steam turbine governor
Anti-surge control
Capacity control
Bearing temperature monitoring
Bently Nevada 3500 radial vibration and axial position monitoring
Oil system monitoring
Start, stop, alarm and shutdown sequencing
Inherent fault tolerance – no single point of failure
Ability to operate with three, two, or one main processor before shutdown
Fully implemented and transparent triplication
Comprehensive system diagnostics
Simple, on-line module replacement